How can I change Professional Income to Business Income in T2125 form? Business Income is greyed out.

[i_int_t]

Hi! Assuming you're using TTO and have already entered an amount as Professional Income. There is no way to modify an entry directly so the quickest way to resolve it is to delete the original entry and re-add the amount as Business Income.
You can find additional details here: https://turbotax.intuit.ca/tips/t2125-tax-form-declare-income-and-expenses-from-a-business-or-profes...